* any datasources with embedded Credentials work fine for both Live and Extract.

* datasources, set to Prompt for database username/password, once the Sign-In prompt comes up, after you put in username/password, it does not seem to pass on those values anywhere, just flashes, and then present the same prompt again and again, regardless of what credentials are put in.

* if the Sign-In prompt is removed by clicking on a cross in its top right corner, it then presents a message 'problem connecting to the datasource'

I have not seen other reports of this unexpected behavior. To get a better better undertstanding of what is occurring with the sign in. Please provide some of the following information.

If the data sources are republished does the recurring prompt for user sign in continue to occur? Does this occur with all data sources on the Tableau Server? What type of data source are encountering the issue? Are they all the same type of data source?